121749128657 has 16 divisors (see below), whose sum is σ = 135428267520. Its totient is φ = 108690768000.

The previous prime is 121749128653. The next prime is 121749128689. The reversal of 121749128657 is 756821947121.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 121749128657 - 2² = 121749128653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121749128599 and 121749128608.

It is not an unprimeable number, because it can be changed into a prime (121749128653) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 559157 + ... + 745757.

It is an arithmetic number, because the mean of its divisors is an integer number (8464266720).

Almost surely, 2^121749128657 is an apocalyptic number.

It is an amenable number.

121749128657 is a deficient number, since it is larger than the sum of its proper divisors (13679138863).

121749128657 is a wasteful number, since it uses less digits than its factorization.

121749128657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188264.

The product of its digits is 1693440, while the sum is 53.

The spelling of 121749128657 in words is "one hundred twenty-one billion, seven hundred forty-nine million, one hundred twenty-eight thousand, six hundred fifty-seven".